1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to the enhancement of display property of a display panel of the display device.
2. Description of Related Art
Conventionally, with respect to a liquid crystal display device which includes a liquid crystal display panel formed by sealing a liquid crystal material between a pair of substrates, for example, there has been known a lateral-electric-field driving liquid crystal display device such as an IPS (In-Plane-System) liquid crystal display device. A liquid crystal display panel which is used in the lateral-electric-field driving liquid crystal display device forms pixel electrodes and common electrodes (also referred to as counter electrodes) on one substrate out of the pair of substrates.
Here, the common electrodes are, for example, connected with a common voltage supply line which stereoscopically intersects a plurality of scanning signal lines or a plurality of video signal lines formed on the substrate. Here, outside a display region of the substrate, for example, an annular common bus line which surrounds the display region is arranged, and the common voltage supply lines are connected with the common bus line.
The voltage of the common potential applied to the common voltage supply lines and the counter electrodes is, for example, generated by a common voltage generation circuit which is formed on a printed circuit board having a timing controller (T-CON). Then, the voltage of the common potential is supplied to the common bus lines from a plurality of printed circuit boards which is connected with the display panel (substrate).
Further, the common voltage supply line intersects the plurality of scanning signal lines or the plurality of video signal lines stereoscopically and hence, intersection capacitances which are generated on intersection regions generate noises, and there exists a possibility that irregularities are generated with respect to potential of the common voltage supply lines (common electrodes). Accordingly, in the liquid crystal display panel of recent years, the potential of the common voltage supply lines is measured, and the potential is fed back to the voltage of the generated common potential thus lowering the irregularities of potential of the common voltage supply lines (common electrodes) (see JP-A-2002-169138 (corresponding U.S. Pat. No. 6,756,958) (patent document 1), JP-A-9-218388 (corresponding U.S. Pat. No. 5,831,605) (patent document 2), for example).